The Potential Protective Effects of 2-aminoethyl Diphenylborinate against Inner Ear Acoustic Trauma: Experimental Study Using Transmission and Scanning Electron Microscopy

Abstract

OBJECTIVE:In this prospective experimental study, we investigated the preventive effects of 2-aminoethyl diphenylborinate (2-APB) in rats exposed to acoustic trauma (AT). Light microscopic, transmission electron microscopic (TEM), and scanning electron microscopic (SEM) examinations were performed. MATERIALS and METHODS:Eighteen healthy Wistar albino rats were divided into the following three groups: groups 1 (control), 2 (AT), and 3 (AT+APB). The rats in groups 2 and 3 were exposed to AT; in group 3 rats, 2-APB at 2 mg/kg was also administered, initially transperitoneally, after 10 min. RESULTS:During the light microscopic, TEM, and SEM examinations, the structures of the cochlear hair cells, stereocilia, and Deiter's cells were normal in the control group. In the AT group, the organ of Corti and proximate structures were damaged according to the light microscopic examination. During the TEM examination, intense cellular damage and stereocilia loss were detected, while during the SEM examination, extensive damage and stereocilia loss were observed. Decreased damage with preserved cochlear structure was detected during the light microscopic examination in the AT+APB group than in the AT group. During the TEM and SEM examinations, although stereocilia loss occurred in the AT+APB group, near-normal cell, cilia, and tectorial membrane structures were also observed in the AT+APB group compared with the AT group.CONCLUSION: 2-APB may have protective effects against AT damage of the cochlea. The main mechanism underlying this effect is the inhibition of the vasoconstriction of the cochlear spiral modiolar artery, thereby improving cochlear blood flow. We conclude that 2-APB may also be effective if used immediately following AT.

Effect of moderate intensity noise exposure on the cochlea of adult male guinea pig and the possible protective role of Pravastatin: Histological study

“…Similarly, other authors [17] observed extensive damage, loss of stereocilia and holes in the apical membranes of OHCs and IHCs originated from the bursting of blebs formed at the apical pole of the stressed hair cells to release cellular material into the endolymphatic compartment. They observed these findings by SEM and TEM examination after acoustic trauma.…”

“…due to noise over stimulation causes increased resistance in the vascular smooth muscle cells that can lead to cochlear damage due to the vasoconstriction of SMA [17] .…”

Primary Cultivation and Identification of Vascular Smooth Muscle Cells from the Spiral Modiolar Artery of Guinea Pigs

“…Hence, if abnormal changes occur in the SMA, such as vasospasm, this change would reduce or even completely interrupt the cochlear blood supply. This condition contributes to blood circulation disorders in the inner ear and cochlear dysfunction, such as dizziness, tinnitus, and other symptoms [8,10]. Hence, the blood supply of SMA may have a decisive impact on maintaining normal hearing [11].…”